"On-Water" Interfacial Acidification Enhances Direct Ammonolysis of Triglycerides.

Area of Science:

• Chemical Engineering
• Organic Chemistry
• Materials Science

Background:

• Direct ammonolysis of triglycerides is an industrial method for aliphatic amide production.
• This process typically requires a large excess of ammonia, posing environmental and economic challenges.
• Optimizing reaction conditions and catalysts is crucial for improving efficiency and sustainability.

Purpose of the Study:

• To investigate the use of emulsions stabilized by perfluorosulfonic acid (PFSA) particles to enhance triglyceride ammonolysis.
• To compare the efficiency of this novel method with conventional liquid ammonia ammonolysis.
• To understand the mechanism behind the observed rate enhancement.

Main Methods:

• Utilizing glyceryl trilaurate (GTL) as a model triglyceride.
• Performing ammonolysis in GTL-in-water(acetonitrile) emulsions (50:50 v/v) stabilized by Aquivion PFSA particles.
• Conducting reactions at 150°C with controlled, lower ammonia excess (47:1 mol/mol ammonia/GTL).
• Comparing results with non-emulsified systems and conventional ammonolysis with higher ammonia excess (148:1 mol/mol ammonia/GTL).

Main Results:

• A sevenfold enhancement in the rate of lauramide formation was observed in the emulsified system.
• Lauramide yield after 5 hours was nine times higher compared to conventional ammonolysis.
• The enhanced activity was achieved at a significantly lower ammonia excess.
• The mechanism involves "on-water" selective acidification at the oil-water interface facilitated by PFSA particles.

Conclusions:

• Emulsion-based ammonolysis stabilized by PFSA particles offers a highly efficient route for aliphatic amide synthesis.
• This method significantly increases reaction rates and yields while reducing ammonia consumption.
• The findings suggest a promising, more sustainable approach for industrial amide manufacturing.